TLE7259G_07 Datasheet, PDF (6/27 Pages) Infineon Technologies AG – LIN Transceiver

TLE7259G
Functional Description
Table 2 Operating modes
Mode EN INH
TxD
RxD
LIN Bus Comments
Termination
Sleep Low Floating Low
High¹⁾ High
Impedance
No wake-up request detected
Stand-By Low High
Low²⁾
High³⁾
Low 30 kΩ
High ¹⁾ (typical)
RxD “Low” after local or bus wake-up
RxD “High“ after power-up
TxD strong pull down after local wake-up (WK
pin)²⁾
TxD weak pull down after bus wake-up or power-
up³⁾
Normal High High
Low
High
Low
High
30 kΩ
(typical)
RxD reflects the signal on the LIN bus
TxD driven by the micro controller
1) Pull-up resistor to micro controller power supply (V_IO) required (see Figure 11 and Figure 12).
2) TxD indicates logical “Low“ in case the micro controller output is set to “High“ and the micro controller output current is
limited to less than 1.9 mA.
3) TxD indicates logical “High“ in case the micro controller output is set to “High“.
4.2
Normal Operation Mode
The TLE7259G enters the normal mode after the micro controller sets EN = high (see Figure 3). In Normal
operation mode the LIN bus receiver and the LIN bus transmitter are active. Data from the micro controller is
transmitted to the LIN bus via the TxD pin, the receiver detects the data stream on the LIN bus and outputs it to
the RxD pin.
4.3
Stand-By Mode
The Stand-By mode is entered automatically after:
• A power-up event on the supply V_S.
• A wake-up event on the LIN bus.
• A local wake-up event on the pin WK.
• A power on reset caused by power supply V_S dropping below V_S,UV,PON (V_S < V_S,UV,PON).
In Stand-By mode no communication on the LIN Bus is possible. The output stage is disabled and the LIN Bus
termination remains activated. The RxD and TxD pins are indicating the wake-up source. The RxD pin remains
“Low“ after a local and bus wake-up event. A power-up event is indicated by a logical “High“ on RxD pin. The signal
on the TxD pin indicates the wake-up source, a weak pull-down signals a bus wake-up event and a strong pull-
down signals a local wake-up event caused by the WK pin (see Table 2). In order to detect a wake-up event via
the TxD pin, the external micro controller needs outputs needs to provide a logical “high” signal. The wake-up flags
indicating the wake-up source on the pins TxD and RxD are reset by changing the operation mode to Normal
operation.
The signal on the EN pin remains “Low“ due to an internal pull-down resistor. Setting the EN pin to “High“, by the
micro controller the device returns to Normal operation mode. Entering the Stand-By mode switches the INH
output to V_S. Depending on the operation mode of the TLE7259G external circuitry, like a voltage regulator, can
be controlled by the INH output.
Data Sheet
6
Rev 2.1, 2007-04-27